Cooperating Layered Architecture for SDN (CLAS)

<draft-contreras-sdnrg-layered-sdn-02>Luis M. Contreras

Telefónica

Carlos J. Bernardos Universidad Carlos III de Madrid (UC3M)

Diego R. LópezTelefónica

Mohamed Boucadair France Télécom/Orange

Dallas, SDNRG WG, March 2015

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Rationale• Existing proposals for SDN centralize control capabilities

with very different objectives and purposes• No separation between services and transport control

– No clear responsibility for service provision and delivery– Complicated reutilization of components for delivering different

services– Monolithic control architectures, driving to lock-in– Difficult interoperability, then difficult interchange of some

modules by others– No clear business boundaries– Complex service/network diagnosis and troubleshooting

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Cooperating Layered Architecture for SDN• Key concept: separation of the control functions associated to

services from those associated to transport– Service control becomes independent from transport control

• Functional Strata– Service stratum: functions related to the provision of services (including

capabilities exposed to external applications) – Transport stratum: functions related to the transfer of data between

communication end-points• Plane separation

– Control plane: control of resources in each strata– Management plane: management of resources and control plane in each

strata– Resource plane: resources required for a given service (can be or not the

termination points of a transport function)• Despite differentiation, tight cooperation is needed for an efficient

service provision

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Cooperating Layered Architecture

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Cooperating Layered Architecture – Topics to address

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• Means to expose transport capabilities to external services

• Means to notify service intelligence with underlying transport events

• Means to instruct the underlying transport capabilities to accommodate new requirements

• Means to capture service requirements of services

ABSTRACTION

ClientRelationship

Transfer of Data

Service Provision

and Capabilities to

External Applications

(*) Depending on the kind of Service the resources at Service Stratum could be or not the End-Points of the Transport Resources

(*)

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Additional topics to address• Multi-domain scenarios in Transport Stratum

– Transport resources being part of different administrative, topological or technological domains

• Recursiveness– Transport Stratum is itself structured in Service and

Transport Stratum

• Security and trust– Security in the communication between strata

• Event notification, OAM, diagnosis

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Deployment Scenarios• Full SDN environment

– Multiple Service Strata associated to a single Transport Stratum

– Single Service Stratum associated to a multiple Transport Strata

– (And 1:1 and N:N cases, of course)

• Hybrid environments– SDN-based Service Stratum associated to a legacy

Transport stratum– Legacy Service Stratum associated to a SDN-based

Transport stratum792th IETF, Dallas

Potential use cases / scenarios – e.g., NFV (*)

8(*) Telefónica, “Operational separation of SDN control for Service-oriented and Connectivity-oriented actions in the framework of NFV”, NFVEVE(15)000066

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Next Steps• Collect interest from the community

– E.g., Ericsson Research contributing in multi-domain scenarios (more details in next draft version)

• Work in the following areas:– Document a gap analysis– Define and document different use cases– Describe requirements for interface definition between

strata– Security (in the communication between strata)– Others(e.g., monitoring, inter-domain provision, SLA, etc)

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